Homogeneous Or Heterogeneous Reactions

Chemical reaction simply define as a reaction in which a substance (or a compound) is converted into a new one with different property. In a reaction, the substance (or a compound) which is converted into new substance (or changes their state) is called 'Reactant' and a newly formed substance is called 'Product'. 
A chemical reaction is usually written by placing an arrow symbol between the reactants and the products. For example, if A and B are two reactants in a chemical reaction while C and D are two products, then this reaction can be represented as -
                A  +   B       ➝     C   +   D
           (Reactants)          (Products) 

Some chemical reactions take place in the same phase ,i.e., all the reactants and products are in the same phase (like in solid, liquid & gas). Whereas some other reactions take place in more than one phase ,i.e., the reactants are in one phase and the products are in the other. 

On this basis chemical reactions are of two types: Homogeneous and Heterogeneous.........
In this article, we will learn about homogeneous and heterogeneous chemical reactions with the help of examples.

Homogeneous & Heterogeneous Reactions 
Based on the state of the substance present in the reaction, chemical reactions are two types namely; Homogeneous and Non-homogeneous Reactions.
The term homogeneous refers to Same, and heterogeneous refers to Different.

HOMOGENEOUS REACTION
......"A homogeneous reaction is defined as a reaction in which all the reactants and the products are in a single phase except solid phase (most commonly either in a gas or liquid phase)"........
In a simple way, There are three states of matter; solid, liquid and gas. If the reactants of a homogeneous reaction are in the gas phase, then the products given by that reaction are also in the gas phase.

Usually, the reactants and products are in the same solution. We call this type of reaction mixture as homogeneous mixture.
For Example
(1) Synthesis of ammonia in which all reactants (N₂ and H₂) and products (NH₃) are in gas phase.  
                   N₂(g) + 3H₂(g) ➝ 2NH₃(g)
(2) The reaction between carbon monoxide and oxygen in the air;
                   2CO(g) + O₂(g) ➝ 2CO₂(g)
(3) The reaction between HCl and NaOH in water;
      HCl(l) + NaOH(l) ➝ NaCl(l) + H₂O(l)
(4) Mixing of sulfur dioxide gas and oxygen gas gives sulfur trioxide gas;
           2SO₂g) + O₂(g) ⇌ 2SO₃(g)

NONHOMOGENEOUS REACTION
.......""A non-homogeneous or heterogeneous reaction is defined as a reaction in which products and reactants are in different phases"......
(like if one reactant is in gas phase than the other reactant is in liquid phase and the product is in solid phase) 
Any reactant and product can therefore exist in one of three phases: solid, liquid, or gas. For this reason, heterogeneous reactions lack homogeneity.
For Example
(1) Mixing of carbon in solid form with oxygen gas gives carbon monoxide gas;
            C(s) + O₂(g) ➝ CO(g)
(2) Magnesium in solid form with hydrochloric acid in liquid gives magnesium chloride and hydrogen gas;
         Mg(s) + 2HCl(l) ➝ Mg-Cl₂ + H₂(g)
(3) The reaction between sodium metal and water.
(4) Iron rusting underwater
(5) The reaction between salt and water
(6) Coal burning in air


Difference Between Homogeneous and Non-homogeneous /Heterogeneous Reactions
  1. Homogeneous reactions are those reactions in which all the reactants and products are in same phase while Non-homogeneous reactions are those reactions in which reactants and products are in different phase. This is the key difference between the homogeneous and the heterogeneous reactions.
  2. Homogeneous reactions have more uniformity than heterogeneous reactions.
  3. Homogeneous reactions are simple while heterogeneous reactions are complex in nature.
  4. Since, there is only one phase in homogeneous reactions therefore homogeneous reactions depends only on the nature of interaction between reactants whereas heterogeneous reactions depends on both the phase of matter and the interaction between reactants.
  5. N₂(g) +3H₂(g) ➝ 2NH₃(g) ➤ Homogeneous Mg(s) + HCl(l) ➝ Mg-Cl₂(aq) + H₂(g) ➤Heterogeneous

Hope you have found this article helpful!!
Do you have suggestions? Please write in comment box!!!
Feel free to comment if you have any queries!!

Comments

Post a Comment

Most Viewed Posts

Zeroth Law Of Thermodynamic: The Thermal Equilibrium Law

Image
In thermodynamics, we will see two types of walls. One is the Diathermic wall and the other is the adiabatic wall. Let us now go through them one by one.  • So the first is the Diathermic wall- " A Diathermic wall is a wall that allows the easy exchange of heat between two bodies (or between two systems or between system and surrounding) but does not allow the exchange of mass between them ". This means that it is a good conductor of heat. It is sometimes called as metallic wall because it is made of metal. • While the other is the adiabatic wall- " An Adiabatic wall is that wall which neither allows exchange of heat nor mass between two systems (or between system and surrounding) ". Since there is no exchange of heat and mass between the system and its surroundings, the system remains insulated from its surroundings. ➛ That's why whenever we separate the two systems by an adiabatic wall, then there is no concept of equilibrium between them. But whenever we sep...
Read more

Characteristics Of Entropy

Image
Entropy is an intrinsic property of a substance and is not affected by the external position of a system or its motion relative to other systems. It is a measure of the randomness of the system. Thus, the higher the randomness of the system, the higher the entropy of the system and the lower the randomness of the system, the lower the entropy of that system. Entropy   " Entropy is defined as a measure of the system's thermal energy that is incapable of doing work ". It is a state function.  For Example Heat is a form of energy that is incapable of doing work. Therefore, the more heat added to the system (or tranfer from the system), the higher (or the lower) will be its entropy.  The formula for change in entropy is given by the equation;                      ➩ ∆S = ∆Q/T For a reversible process, the change in entropy is given as; The Total Change In Entropy Entropy change is zero at equilibrium condition or whenev...
Read more

Reversed Carnot Cycle

Image
We have already discussed the concept of “ Carnot Cycle ”   & “ Its Efficiency ” and we have also seen the concept of “ Carnot Theorem And Its Explanation ” in our previous post. As we have already discussed that the Carnot Cycle is a reversible cycle and every process in the Carnot cycle is a reversible process. Therefore, every process of the Carnot cycle can be reversed. And the cycle can be operated in the opposite direction as well. In this article, we're interested in learning more about the reversed Carnot cycle, also known as the reversed Carnot heat engine cycle. Reversed Carnot Heat Engine It is important to note that if a reversible process is reversed, all related energy types—such as heat energy or work energy—will have the same magnitude but the direction of their interaction with matter will be changed. Let us first look at the Reverse Carnot Heat Engine  cycle here; The reversed Carnot heat engine cycle is depicted in the following figure. According to the...
Read more